IPad: Why missing photos when sync photos and video using iTunes with the Mac

You can use something like iPhone Explorer to drag and drop them into the /User/Media/DCIM/100Apple (last one may be different) directory. I know it works with pictures, but I haven't had a chance to test with video. But I don't see why it wouldn't work once the database is updated.

If you're jailbroken and transfer a video, that the phone can play, with iPhone Explorer (works on Mac and Windows for iPad and iPod too) or through SSH (with the OpenSSH package from Cydia), iFile can add it to the camera roll (same with pictures, and it doesn't matter where they are if you use the SSH and iFile method). Not exactly drag and drop but you don't have to go through iTunes. iPhone Explorer does not require the iDevice to be jailbroken.

Also if you got the VLC Player app before Apple pulled it you can drag and drop almost any video type into the app via the "File Sharing" box in iTunes in the App tab. (If the phone is jailbroken you can still get the VLC player from Cydia)

I have had iTunes go off the deep end thinking there were far too many photos.

I have had luck with several tacks so I presume there are a few bugs - one of which you may have run into:

1. Take the device to another computer (or another iTunes library on a shell account) and let it sync and erase all photos on iOS. Taking it back to the main iTunes library which has the correct photos sometimes works. I presume the error was an accounting one on the iPad when this works.
2. Change photo sync to a simple folder with a jpeg or two, sync it, and then change back to the settings I prefer. (rarely works)
3. Rebuild the affected library in Aperture or iPhoto - this seems to force new data into the media browser so iTunes is forced to take a better look at the sizes for your albums and photos as organized.

Sorry I don't have a sure fire answer - but maybe you haven't tried all of these or it sparks an idea of something else you can try.